But again, Joyce hit back. "Are you saying that if Australia changes its domestic policies then the climate will change?.

"This idea that Australia unilaterally will make a decision that is going to change the climate is absurd."

Prof Mann said some world leaders are "basically sabotaging climate action for the entire planet".

"You can count (these countries) on the fingers of your hand. It's Saudi Arabia, it's Russia, it's the United States and Brazil. Does Australia want to be part of that family?"

But Mr Joyce said Australians will lose their "dignity" if coal exports stop and weaken Australia's economy.

"If you want to sell this program, you have to say to (the Australian people) how you're going to make their lives more affordable and put dignity back into their lives," he said.

Army General Major General Peter Dunn then jumped in with angry response.

"But what dignity have you got, Barnaby, when you are standing in the middle of rubble and saying 'how on earth did this fire happen?'," he said.

He said the "head of the serpent" fuelling bushfires is climate change.

"This country wants politicians to step up. It is the existential issue that the public have raised," he said.

"It defeats me as to why you won't step up to it. All (scientists) predictions have, damn it, turned out to be right."

ZERO CARBON EMISSIONS TARGET 'ABOUT EMOTION'

Liberal senator Eric Abetz says the prime minister should not commit to a net-zero emissions by 2050 emissions target.

It comes as the government considers a long-term emissions reduction strategy to take to the COP26 meeting in Scotland.

Mr Abetz said a long term target was based on the "emotion and not about the substance of the issue".

"Trying to forecast to 2050 is 30 years in advance. If you were to wind the clock back 30 years and say 'did men and women 30 years ago predict what is happening today?' The answer is no," Senator Abetz told Sky News.

"Similarly, trying the figure on 2050, why 2050 why not 2040 or 2060? That is all about I think the emotion and not about the substance of the issue.

"What we need to deal with is ensuring we have a sustainable energy supply while reducing our emissions as much as possible."